How Long Does a Ball Take to Hit the Ground from a 12.5m Building?

[jameo15]

Physics 12 Kinematics Question.. Please Help!

Homework Statement

A ball rolls off the top of a 12.5m building with a speed of 3.4m/s. How long does it take to hit the ground? What is the range from the base of the building?

Homework Equations

V = V₀ + at
V²=V₀² + 2ad
Avg V = (V = V₀) /2
d = V₀ + 1/2 at²

The Attempt at a Solution

All I've got was a sketch drawn.. Please help me. Well I timed 12.5 by 3.4 to get how long it took to hit the ground but I'm not sure if it is right. I'm guessing to find the range you must need an angle of some sort?

 

[Hootenanny]

Homework Statement

A ball rolls off the top of a 12.5m building with a speed of 3.4m/s. How long does it take to hit the ground? What is the range from the base of the building?

Homework Equations

V = V₀ + at
V²=V₀² + 2ad
Avg V = (V = V₀) /2
d = V₀ + 1/2 at²

The Attempt at a Solution

All I've got was a sketch drawn.. Please help me. Well I timed 12.5 by 3.4 to get how long it took to hit the ground but I'm not sure if it is right. I'm guessing to find the range you must need an angle of some sort?

Welcome to PF jameo15,

You need to consider the horizontal and vertical components of motion separately. When the ball rolls off the building, just at the point where it leaves the surface, what is it's vertical speed?

 

[jameo15]

Would it's vertical speed be the acceleration due to gravity? But at the point where it leaves the surface, it should be zero right?

 

[Hootenanny]

Would it's vertical speed be the acceleration due to gravity?

No, but that would be it's acceleration.

But at the point where it leaves the surface, it should be zero right?

Correct. So using this information, can you determine how long it takes to hit the ground (just considering vertical motion).